OP0186 SENSITIVITY TO CHANGE OF DIFFERENT ULTRASOUND SCORES IN A PROSPECTIVE FOLLOW-UP OF NEW-ONSET TREATMENT-NAÏVE GCA PATIENTS.
Authors: B. D. Nielsen, P. Therkildsen, K. Keller, L. C. Gormsen, I. Hansen, E. M. Hauge
Journal: Annals of the Rheumatic Diseases (2022)

Background The role of ultrasound (US) for monitoring giant cell arteritis (GCA) is not clarified. Follow-up assessment of number of halos (halo count) and different quantitative scores based on intima media complex (IMC) measurement of halos, have demonstrated potential to show sensitivity to change (STC) 12 . Including IMC of normalized arteries in such scores may reduce the risk of missing new arteritic lesions and assessment bias towards a response. We aimed to evaluate US scores based on halo features and scores based on IMT measurements of all assessed arteries. Objectives To compare different US score’s 1) STC after institution of treatment and 2) correlation with disease activity. Methods In a prospective cohort of new-onset GCA patient, pre-treatment diagnostic evaluation including US and PET/CT and subsequently temporal artery biopsy (TAB) was performed per protocol. All patients were started on 60 mg of prednisolone and followed a routine tapering. Follow-up visits including clinical evaluation, blood tests, US, the physician’s and patient’s global NRS (0-10) were performed after 8 weeks, 24 weeks and in a subgroup (n=24) at 15 months. US of temporal, carotid and axillary arteries included assessment of halo and IMC measurement in all arteries. For each visit, max IMC, max halo IMC, sum IMC, sum halo IMC, mean IMC and halo count were calculated for all and for temporal (TA) and large vessels (LV) separately. Accordingly, halo IMC scores only included positive arteries whereas other IMC scores included all arteries assessed. The change from baseline was assessed by Student’s t -test. Standard response means (SRM=meanΔ(visit-baseline)/SE Δ ) were computed for each timepoint as STC estimates. Correlation with disease activity markers was assessed by Spearman’s correlation. A p&lt;0.05 was considered statistically significant. Results In total 47 patients were included (60% women, mean (CI) age 67 (62-69) years, mean (CI) CRP 75 (63-89)). Baseline US was positive(+) in 94% (72% TA+, 72% LV+), PET/CT+ in 96% (77% cranial arteries, 85% large vessel vasculitis) and TAB+ in 72% of patients. All patients completed the per protocol planned follow-up visits. Two patients experienced a relapse at week 8 and 10 patients at week 24. All US outcomes improved during follow-up and was apparent by week 8 (Table 1) and forward. However, only scores including TA consistently showed statistically significant change from baseline to follow-up. In accordance the magnitude of change as expressed by SRM was large in TA, whereas SRM in LV was small (Figure 1). All TA based US scores showed significant moderate-strong correlation with disease activity markers (CRP, patient and physician global NRS). Some LV based US scored showed weak correlation with CRP but otherwise did not correlate with clinical disease activity. Figure 1. Table 1. US score changes during follow-up Baseline (IQR ) Δw8 (SE ) Δw24 (SE ) Δm15 (SE ) Halo count TA 2 (0-4) -1.68 (.28 ) -1.70 (.30 ) -2.63 (.37 ) LV 1 (0-2) -0.04 (.11 ) 0.00 (.11 ) 0.00 (.31 ) Total 4 (2-6) -1.72 (.33) -1.70 (.34) -2.63 (.36) Sum IMC TA 0.8 (0-1.8) -0.72 (.08 ) -0.69 (.11 ) -0.76 (.19 ) LV 1.5 (0-2.8) -0.33 (.12 ) -0.13 (.11) -0.33 (.21) Total 2.6 (1.6-4.4) -1.05 (.14 ) -0.81 (.15 ) -1.09 (.29 ) Sum halo IMC TA 1.9 (1.6-2.5) -0.90 (.14 ) -0.90 (.17 ) -1.29 (.23 ) LV 3.5 (2.8-4.0) -0.33 (.17) -0.15 (.14) -0.47 (.39) Total 5.5 (4.6-6.3) -1.23 (.24 ) -1.04 (.24 ) -1.76 (.35 ) Max IMC TA 0.5 (0.4-0.6) -0.17 (.03 ) -0.14 (.03 ) -0.17 (.05 ) LV 1.2 (0.9-1.6) -0.16 (.06 ) -0.04 (.05) -0.20 (.09 ) Max halo IMC TA 0.5 (0-0,6) -0.29 (.04 ) -0.26 (.05 ) -0.40 (.05 ) LV 1.2 (0-1.6) -0.27 (.09 ) -0.09 (.08) -0.23 (.17) Mean IMC TA 0.32 (0.27-0.43) -0.11 (.01 ) -0.10 (.02 ) -0.13 (.03 ) LV 0.88 (0.7-1.03) -0.9 (0.3 ) -0.04 (.03) -0.10 (.05 ) Baseline medians, Δ mean difference from baseline. Bold indicates p&lt;0.05. Conclusion STC was maintained in US scores that included all assessed arteries hereby reducing potential assessment bias. These findings confirm US as a potential tool for monitoring treatment response. References [1]Ponte C, et al . Ann Rheum Dis 2021 [2]Seitz L, et al. Rheumatology 2021 Acknowledgements The authors would like to thank Morten Frydenberg for statistical support. Disclosure of Interests Berit Dalsgaard Nielsen Speakers bureau: Roche, Paid instructor for: Roche, Consultant of: Sanofi, Philip Therkildsen: None declared, Kresten Keller: None declared, Lars Christian Gormsen: None declared, Ib Hansen: None declared, Ellen-Margrethe Hauge Speakers bureau: AbbVie, Sanofi, Sobi, MSD, UCB, Consultant of: AbbVie, Sanofi, Sobi, MSD, UCB, Grant/research support from: funding to Aarhus University Hospital from Roche, Novartis, Abbvie